Isolation, Characterization, and Seroprevalence of Serotype-1 and 4 Fowl Adenoviruses in Chickens in Taiwan

由源自兩個種雞場之無臨床症狀一日齡小雞分離到八株家禽腺病毒（FAV），經萃取分離株之DNA進行基因型鑑定、PCR與限制酶切割反應、病毒中和試驗，皆可將此八株至于離株區分為A（第1血清型，FAV-1）及C（第4血清型，FAV-4）基因群。取A與C基因群分離株各三株各口服接種10^3 TCID（下標 50）於一日齡無特定病原（SPF)小雞，包括注射cyclophosphamide之免疫抑制組。結果六株分離株所引起之死亡率，不論有無免疫抑制均無顯著差異；A基因群分離株無免疫抑制之雞隻增重與對照組之間無顯著差異，但其中兩株於免疫抑制下之增重顯著低於對照組（p＜0.05）；相反地，三株c基因群分離株無免疫抑制時之雞隻增重即顯著低於對照組（p＜0.05）。調查台灣各雞種之FAV-1與FAV-4之中和抗體，結果小於2週之白肉雞與有色雞其抗體陽性率分別為58.1-60.7%與12.9-16%。在25週齡以上之種難抗體陽性率分別為46.4%（FAV-1）與12.1%（FAV-4）。

關鍵字

家禽腺病毒；血清學調查；血清型；基因群；病原型性

並列摘要

Fowl adenoviruses (FAVs) were isolated from eight one day-old healthy broilers originated from two parent flocks. FAVs were characterized by the whole DNA genomic typing, hexon-based polymerase chain reaction combined with restriction enzyme analysis of the amplified DNA fragment, and by virus neutralization using serotype specific antisera. The isolates belonged to either DNA group A/serotype 1 (FAV-1) or DNA group C/serotype 4 (FAV-4). The pathogenicity of these isolates was studied in day-old specifio-pathogen-free (SPF) chicks. Each chick was orally inoculated with one strain of the virus at a dose of 10^3 TCID(subscript 50). FAV-4 isolates significantly decreased weight gain, whereas FAV-l isolates did 50 only when the chicks were also immunosuppressed with cyclo-phosphamide. Examination of various chicken flocks in Taiwan revealed seroprevalence rates of 58.1-60.7 % for FAV-l and 12.9-16 % for FAV-4 in broilers and hybrid broilers younger than two weeks of age. After the decline of maternal antibody, the positive rate in hybrid broiler rose again and increased from eight weeks of age onwards. In breeder chickens older than 25 weeks of age, the seroprevalence rates were 46.4% (FAV-1) and 12.1% (FAV-4).

並列關鍵字

DNA groups ； Fowl adenovirus ； Pathogenicity ； Seroprevslence ； Serotype

國際替代計量

Isolation, Characterization, and Seroprevalence of Serotype-1 and 4 Fowl Adenoviruses in Chickens in Taiwan

全文下載

主題瀏覽